Win8 upgrade Win8.1 preview version is not lost data /application

        Microsoft announced the launch of the Windows 8.1 preview beta in Build2013. Just like every Windows system upgrade, everyone has always been very concerned about the migration of personal data, software and other materials; in the Windows 8.1 era, the situation is roughly like this:
• Win8 upgrade to Win8.1 preview: you can keep the "Windows settings" , personal files and most applications"
• Win8 upgrade directly to Win8.1 official version: you can keep "Windows settings, personal files and most applications"
• Win8.1 preview upgrade to Win8. 1 official version: User data such as "personal files, account information" can be retained, but all applications need to be reinstalled.
The data that can be retained when upgrading to Win8.1 preview is different. For details, please see:

Note: When you install a subsequent version of Windows 8.1, you will be able to keep personal files. , but need to reinstall the app.